Dislocations in the hand are common injuries in sports and in occupational settings, often appearing to be minor. If the athlete, trainer, or coach has already reduced the dislocation, it appears unimpressive compared to a major knee injury or a shoulder dislocation. However, these injuries have real potential for long-term disability in sports and other areas of life if adequate reduction is not performed, if associated injuries are not identified and appropriately treated or referred, and if potential complications of the injury and its treatment are not foreseen. The judgment of the initial treating physician can be critical in determining the long-term outcome.

In addition to PIP and DIP dislocations in order of decreasing frequency, metacarpophalangeal (MCP) joint dislocations and carpometacarpal (CMC) dislocations also occur. The MCP joint of the 4 fingers usually dislocates posteriorly (simple type) but can, on the rare occasion, become entrapped between the palmar fascia and the palmar plate and become irreducibly dislocated. The CMC joint dislocation is a disabling injury, which is usually dorsal, and may be associated with fractures of the bases of the metacarpals.

The bony anatomy of the PIP joint consists of medial and lateral condyles on the proximal phalanx, with matching concavities on the associated distal phalanx. This allows for a wide ROM in flexion and extension, but it is relatively rigid in abduction and adduction, making it a hinge (ginglymus) joint functionally. DIP joint bony anatomy is similar but with surrounding soft tissue providing more restriction in flexion. The extrinsic flexors across both joints are at least 4 times stronger than the extensors, allowing flexion contractures to develop very rapidly, especially with immobilization in flexion. Adequate ROM, especially at the PIP joint, is critical for normal hand function.

Both types of interphalangeal joints are supported by similar soft tissue structures on all 4 sides, which includes the volar plate on the palmar side (the integrity of this structure is essential to a stable reduction), collateral ligaments on the radial and ulnar sides, and the extensor complex (central slip, lateral bands, and hood) dorsally. These structures attach to and reinforce the joint capsule. For a dislocation to occur, at least 1, often 2, and sometimes 3 of these structures must be significantly injured.

The volar plate is a roughly triangular structure with its base oriented distally, attaching to the volar base of the middle phalanx with its tip attaching to the distal aspect of the proximal phalanx. The volar plate functions largely in limiting hyperextension. Thus, it is nearly inevitably injured in dorsal dislocations.

The collateral ligaments restrict the joint from opening to varus or valgus stress and are also commonly injured in dorsal dislocation. Injury to the radial collateral ligament is about 6 times more common than injury to the ulnar collateral ligament. The extensor complex over the PIP joint consists of the central slip, which attaches to the base of the middle phalanx; the lateral bands, which run dorsolaterally on each side; and the transverse retinacular ligament, which connects these structures and extends laterally. These structures help to limit volar movement of the base of the middle phalanx and are thus commonly injured in volar dislocations at the PIP joint, with the middle phalanx either tearing the central slip from its insertion or buttonholing through the transverse retinacular ligament between the central slip and one of the lateral bands.

The MCP joint is thought to be an ellipsoid joint. The head of the metacarpal consists of medial and lateral condyles and is narrower on its dorsal surface than on its palmar surface; it fits into the concavity of the base of the proximal phalanx. The true collateral ligament attaches to a recess created by the junction of the shoulder and head. The collateral ligament is composed of the following 2 parts: (1) a dorsally placed cord portion and (2) a fan-shaped volar portion or accessory collateral ligament, which extends from the metacarpal to the sides of the volar plate. To accomplish flexion and extension at the MCP joint, the anterior and posterior parts of the capsule must be lax. When the joint is extended, the phalanges have considerable lateral play in abduction and adduction and, therefore, this joint avoids frequent injury; however, if the ligament is torn, dislocation occurs.

The bony anatomy of the CMC joint consists of the 5 metacarpal bases that articulate with the trapezoid, trapezium, capitate, and hamate (in that order) from the radial to the ulnar aspect of the hand. The CMC joint is a relatively fixed joint segment because of the articular congruity of the joint surfaces, with the metacarpal bases acting like concave receptacles to the distal carpal row, and because of the strong interosseous and extrinsic ligament complex. The palmar and dorsal ligaments are distinct, with the palmar ligaments being stronger. The scaphoid acts as a link between the proximal and distal carpal rows. The extensor and flexor tendons pass over this articular area but add no strength to the CMC joint because the bases of the metacarpals dislocate dorsally relative to the distal carpal row.

The MCP joint of the thumb has radial and ulnar collateral ligaments, which are loose when the joint is extended and tight when flexed. When the joint is extended, the proximal phalanx has the lateral play achieved by the action of the interosseous muscles. When the thumb is flexed and in a functional position, as in the case of many sports situations (eg, skiing, falls on a gloved hand), the ulnar collateral ligament is the structure at risk and can be ruptured. The ulnar collateral ligament can then be displaced so that the adductor aponeurosis is interposed between the ruptured end of the ligament and its site of bony attachment.

The first CMC joint or the first metacarpotrapezoid joint is a very mobile saddle joint, with articular surfaces that are reciprocally concavoconvex. The most important soft tissue support for this first CMC joint is the deep ulnar or anterior oblique ligament that runs from the volar beak of the metacarpal to the tubercle of the trapezium. This ligament can be ruptured, but it tends to be avulsed with a piece of bone (Bennet fracture dislocation).

Sport Specific Biomechanics: Dislocations of the interphalangeal joints of the hand probably occur most commonly in basketball and football. In basketball, the usual mechanisms of injury include being struck by the ball, catching a finger on the rim, or contact with another player. In football, the finger may be caught on a jersey, slapped against a helmet, or crushed between some combination of other players, their equipment, and the ground. Linemen and defensive players are at highest risk for hand injuries. In both of these sports, return to play almost always requires that the injury can be splinted stably to allow for a power grip.

Dislocations of the MCP and basilar CMC joints occur most commonly with falls on the outstretched hand or the flexed supinated wrist. With this extension vector, the forces are transmitted up through the carpus.

Injuries and dislocations of the thumb, MCP joint, and the CMC basilar joint can commonly occur in falls, with the thumb in abduction. Examples of this type of injury include falls on the gloved hand in baseball or an abduction force applied to a flexed thumb while grasping an object, such as in skiing injuries when the pole impacts the proximal phalanx tearing the radial collateral ligament. This occurs when the wrist is extended at the time of the injury.

As with any hand injury, the history should begin with determining the patient's age; handedness; sex; and type of participation in sports, hobbies, or occupation because these affect both the presentation of the injury and the goals of treatment. The patient most likely presents with a history of trauma leading to finger deformity. The clinician should inquire about whether other injuries took place to rule out the presence of any life-threatening injury.

Because the patient or others involved at the scene often reduce the dislocation, eliciting the mechanism of injury (eg, hyperextension, axial loading, torsion, radial/ulnar stress, direct blow) and the resultant deformity in the history is important. The patient often is not able to clearly describe the mechanism of injury, but the description of the deformity (volar versus dorsal) is valuable because the associated injuries and the appropriate treatment of these 2 injuries differ significantly. The exact location of pain can be helpful in localizing the injury, but this is more precisely defined by tenderness on physical examination.

Most injuries to the carpus occur when the patient falls on the outstretched hand, as might occur in any sport or accident. When the resultant vector is primarily one of ulnar deviation and intercarpal supination, ligamentous disruption and carpal dislocations tend to result. This mechanism can be observed in glove-side injuries in baseball fielders or hockey goalies.

Past medical and surgical history should focus on prior injuries to the hand and underlying conditions that may affect healing.

Physical: Areas that need to be assessed in the physical examination of a hand dislocation injury may include the following:

The following items should be checked postreduction:

Causes:

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The duration and position of immobilization of PIP injuries depends on the structures involved and the severity of any disruptions. Dorsal PIP dislocations that are stable postreduction can generally be treated with buddy taping. This limits hyperextension, preventing recurrent dislocation and allows a combination of AROM and gentle PROM. An alternative is the use of a dorsal aluminum foam splint. In the case of a significant collateral ligament injury, the finger used as a splint should be on the side of the injured collateral ligament whenever possible. Uncomplicated PIP dislocations are usually immobilized in extension for 7-10 days. More serious injuries may be followed by up to 6 weeks of buddy-taped AROM. The patient should follow up within 2 weeks to confirm proper splinting and absence of skin problems.

Following closed reduction of dorsal PIP dislocations, immobilize the joint with a dorsally placed splint in 10-15 degrees of flexion. The patient can begin active flexion while in the splint once comfortable. After 2 weeks, the splint can be discontinued and the finger buddy taped for 2 more weeks. Dorsal PIP dislocations that are unstable in extension (including fracture-dislocations) should be initially treated with extension block splinting at the angle required to keep the joint and the fracture (if present) reduced. This splint is often placed dorsally as an outrigger splint anchored in a short-arm cast with the splint taped to the cast to maintain the flexion angle. The proximal phalanx must be immobilized (taped to the splint) to prevent the patient from achieving too much PIP extension by flexing the MCP joint while the middle and distal phalanges are left free.

Volar dislocations with an intact extensor mechanism that are stable postreduction can usually be treated with buddy taping. If open reduction is required without extensive surgical repair, the joint can usually be immobilized for a few days and then buddy taped. Volar dislocations accompanied by central slip injury require splinting of the PIP joint in extension (leaving the DIP joint free) usually for 4-6 weeks followed by daytime dynamic and nighttime static extension splinting for 2 weeks. The DIP joint should be actively flexed throughout the entire recovery phase.

All of these injuries should be aggressively treated to minimize swelling. Routine elevation consists of propping the forearm and hand up on a pillow at night, wearing a sling, or consciously holding the arm up during the day. Ice is used as needed, especially during the first few days. Wrapping the finger with Coban tape can also be used to treat edema.

For patients seen early after dorsal MCP dislocations that are stable after reduction, rubber band extension block splinting (about 20 degrees) for 2-3 weeks should be tried to prevent recurrence through hyperextension. Collateral ligament injuries should be immobilized in incomplete flexion (50 degrees) for 3 weeks, followed by AROM with the digit buddy taped to protect against lateral deviation stress. Additional physical therapy should be completed with modalities to prevent hand edema and maintain mobilization of all of the joints of the hand.

In CMC dislocations, the hand and wrist are frequently placed in an extension-type splint or cobra-type (extension) cast. Initial therapy should be directed at elevating the hand, decreasing the swelling, and mobilizing all of the stable joints of the hand.

In the early stages of MCP and CMC dislocations, the role of occupational therapy is usually limited. However, aggressive mobilization of the fingers of the hand and the wrist joint are carried out after the dislocation is stable and as early in the course of treatment as possible.

•  Medical Issues/Complications: Appropriate expectations regarding the outcome of any injury should be discussed with the patient.

All patients with these injuries should follow up within a week to check for some of the more common complications. Dorsal PIP dislocations that initially appear stable may develop subluxation with extension, requiring more aggressive treatment. Volar PIP dislocations may also lose reduction, or they may have an occult central slip injury at initial presentation (usually reflected by tenderness over the insertion) that progresses to a complete rupture over the next few days. Stiffness is a common complication at all stages of treatment, especially with PIP dislocations. The patient should perform gentle AROM exercises of any joint that does not require rigid immobilization. Resolution of stiffness and soreness may take as long as 12-18 months, and permanent residual enlargement of the joint is a possibility.

Collateral ligament injuries (usually radial) commonly accompany finger dislocations and usually respond well to closed treatment with no significant long-term disability. However, the patient should be made aware that the pain from these injuries may take months, up to a year, to completely resolve and that permanent enlargement of the joint is a common sequela. Complications associated with MCP and CMC dislocations usually fit into the following 3 categories:

The patient should be monitored in the week following the dislocation to evaluate whether any posttraumatic skin ulceration, slough, or breakdown is present that may need to be treated with wound care or antibiotics. The patients should undergo repeat radiography intermittently early on to verify that the reduction is maintained.

After appropriate immobilization, patients can have evidence of dislocation or subluxation of the extensor tendon to the radial or ulnar side of the MCP joints occupying a place between the 2 metacarpal heads. This is best treated by surgical intervention and proper repair of the torn extensor expansion with a row of interrupted sutures.

In long-term dislocation or recurrences, surgery is suggested to expose the joint dorsally and to perform a capsulectomy on either side of the MCP joint to achieve stable reduction. In some cases of acute MCP joint dislocation, the collateral ligament may rupture where it attaches to the tubercle of the metacarpal. This may lead to recurrent instability but can usually be treated nonoperatively, except when the collateral ligament rupture occurs on the radial side of the MCP joint of the little finger. In this case, the short abductor muscle of the little finger may pull it into ulnar deviation, requiring operative repair.

DIP injuries are considered chronic after 3 weeks. Chronically subluxed joints may require opening to resect scar tissue to allow tension-free reduction.

Complex fracture dislocations may require surgery for some combination of open reduction, internal fixation, and repair of supporting structures. External fixation (compass hinge) has been used on some complex PIP fracture dislocations to provide distraction across the joint, maintain reduction, and allow controlled ROM. Details of surgical therapy for MCP and CMC dislocations were addressed under Procedures.

•  Consultations: A hand surgeon should see any patient who requires or may require surgery. In addition to the above surgical indications, referral to a hand surgeon is usually indicated for fracture-dislocations, most volar dislocations, and any dislocation with associated tendon injury.

•  Other Treatment (injection, manipulation, etc.): Other forms of treatment for hand dislocations are rarely indicated.

Recovery phase:

•  Rehabilitation Program:

•  Medical Issues/Complications: Several complications can arise during this phase. At the first follow-up, the examiner should specifically look for recurrent instability/subluxation in the joint. Early boutonniere deformity (ie, hyperextension at the DIP joint with fixed flexion at the PIP joint) is indicative of a central slip injury and often progresses to a disabling deformity without appropriate treatment. Stiffness can occur in any of these injuries. This can be minimized in most cases by avoidance of excess immobilization and appropriate involvement of occupational therapy and hand surgery at an early stage in high-risk injuries.

In MCP and CMC dislocations, the same problems that are observed in the acute phase can be observed in the recovery phase. However, stiffness becomes a more predominant complication, and it can occur in any of the joints of the fingers, the MCP joints, and the CMC joints. Treatment involves aggressive occupational therapy to prevent joint ankylosis.

•  Surgical Intervention: Most patients needing surgery for these injuries are best served by treatment in the acute phase. If surgery is needed, it is most likely for the reasons below (see Consultations).

•  Consultations: A hand surgeon should be involved early on in the treatment of any complicated PIP or DIP injury. The need for such consultation would be indicated if the patient presents late, was inadequately assessed at initial presentation, or develops an unforeseen complication such as recurrent subluxation in a joint that appeared to be stable after reduction.

•  Other Treatment (injection, manipulation, etc.): Other forms of treatment are rarely indicated.

Maintenance Phase:

•  Rehabilitation Program:

•  Medical Issues/Complications: Most long-term complications of finger dislocations are related to either stiffness or instability. Stiffness is initially best treated with intensive occupational therapy, but a hand surgeon should assess all significant contractures. Lateral instability is usually due to collateral ligament injury, instability in extension to volar plate injury, or a missed fracture. Most volar plate injuries heal with immobilization that prevents hyperextension (usually buddy taping), so this complication often is preventable. Depending on the demands of the sport and position played, the finger and specific structures involved, and the degree of instability, some of these problems may benefit from surgery.

•  Surgical Intervention: A number of procedures are possible to treat instability, stiffness, and fracture nonunions in and around the interphalangeal joints. Severe DIP problems may be treated with arthrodesis depending on the demands placed on the hand. However, this is not a good option for the PIP joint. Any procedure on the PIP joint is likely to result in some loss of ROM. Therefore, compliance with occupational therapy is critical.

•  Consultations: Most patients with chronic instability or stiffness in a finger (especially PIP joint) should be referred for assessment by a hand surgeon.

•  Other Treatment (injection, manipulation, etc.): Steroid injection may rarely be indicated in a chronically swollen painful joint.